Ocean updates served in stragglers, flocks, and set waves

Archive for April, 2007

In case you don’t recall, Phase One involved a shaky estimate of herbaceous stem density in the sideyard of Scribble Central Command: approximately 126,000 shoots of tenacious (though pretty) weeds.

Phase Two actually began the same day, with an attempt to estimate biomass rather than blithely quote shady statistics about “stems.” I was after dry biomass, because I wanted to estimate the amount of carbon in the yard.

Hewing to my no-resource-consumption ethic, I resisted baking the clippings in the oven and instead locked them in my car, windows up, and left them in the sun for a week and a half. Then I bagged up the clippings and took them to the farmer’s market, where I sheepishly asked a vendor to weigh the bag for me and not comment on the suspicious tangles of dried herbs.

This being Santa Cruz, I got a “No problem, dude” and an answer: 0.44 pounds. (Can you change the readout to grams? “Uh, I probably could, but I don’t want to get confused.”)

No matter. A few seconds with Google Calculator and I have an answer of 199.580643 grams in my 0.312 sq-meter bicycle-tire plot. Let’s just call it 200 grams. For the 56% of my yard that rates a “seriously overgrown” designation, that works out to 87.95 kilograms of weeds. To put it another way, that’s roughly one entire Scribbler, spread out over the yard, in bone-dry vegetable matter. If you consider that people are famously 70% water, then we’re really talking about 3 and 1/3 properly dried-out Scribblers to equal the sideyard’s two-month output.

(That is, of course, assuming that all the dry mass is carbon, which criminally ignores all the nitrogen, phosphates, heme groups, etc. that plants contain. Famous weed scientists, including but not limited to Dr. Beth Newingham, are encouraged to contact this blog with adjustments.)

Of course, while plants are busy making things like snapdragons and cherries, they’re also making things like carrots and potatoes. I’ve measured the so-called aboveground biomass and can only guess at the amount of belowground biomass twining through the soil. Plant ecologists try to help us with this by measuring “root-to-shoot” ratios, but turns out the ratios are quite variable. Annual plants have less root and more shoot, as you might expect; perennials store energy for next year in a tap root. Drier land promotes larger roots and smaller shoots.

Still, take a middling number from the range of ratios, let’s say 1:1 to make it easy, and that means there’s the equivalent of another 3-and-a-third Scribbler-masses lying under the ground out there. Creepy.

(Again, plant ecologists are encouraged to weigh in with realistic numbers.)

Can it really be that my humble sideyard has ingeniously sequestered some 180 kilograms of carbon [or, slightly more honestly, 72 kg – thanks moley] from the atmosphere since just this March? I think I need to contact Richard Branson and Al Gore about that $25 million prize they recently announced.

Alas, it’s not quite that simple, as you may have read in the recent post about the Twilight Zone. That carbon is sequestered for only as long as the plant matter remains plant matter. Cut it, compost it, let it die a natural death in winter, feed it to a cow, burn it – do what you like – the carbon will float innocently back into the air and resume trapping heat. Darn.

Still, it’s impressive. Watching grass grow may be boring, but thinking about molecules being snagged out of midair and assembled into a 180-kg forest before your very eyes is something else.

Image: aerial (roof-based) reconnaissance of the SCC sideyard. Readers with expertise in image rectification are invited to help out. The dark, nearly circular splodge in center-right is the bike-tire sampling spot being reclaimed by sun-mad burclover. At bottom left is the completely anonymous Subaru.

Every year, microscopic phytoplankton turn about 50 billion metric tons of carbon into plant life. Much of that carbon comes straight out of the atmosphere. On the surface of things, that sounds pretty good – but a paper in today’s Science reports that below the surface it’s rather more complicated.

The study – called VERTIGO, in one of oceanography’s acronymic triumphs – involved 17 authors and more than 40 scientists from seven countries. They sailed the seas off Hawai’i and Japan, chucking recently invented, free-diving samplers overboard to follow what happens to all that carbon after it becomes phytoplankton. The short answer is, it gets recycled. And while recycling is a good thing to do with bottles and cans, doing it with carbon is counterproductive.

When phytoplankton decomposes near the ocean surface – between 100 and 1,000 meters depth, in a literally gray area called the twilight zone – it results in no net carbon storage. It’s the same reason that burning biodiesel creates no net emissions (the french-fry-scented carbon coming out your tailpipe is just going back where it had been during the last growing season).

Before VERTIGO, hopes had been high that most of those gigatons of phytoplankton sank to the bottom of the ocean, far from the atmosphere, where they could start their million-year conversion to more oil. Evidence from the project suggests that 50 to 80 percent of the carbon never sinks past 500 meters. The amount varied between the tropical and temperate sampling sites. Extrapolate those two estimates across the globe, and that’s a difference of 3 billion tons of carbon reaching the deep ocean. For perspective, that uncertainty is equal to half the world’s current fossil-fuel emissions.

How does the plankton decompose? That’s ecology at work for you. Even though diminishing light shuts out plant life below about 100 meters depth, zillions of intrepid zooplankton squirt around in the twilight zone scavenging falling detritus. The recycling happens over and over as well-fed zooplankton excrete marine snow (one of the most delicate euphemisms ever invented), to be scavenged by deeper, even more intrepid creatures. The result is that surprisingly little carbon makes it from surface waters into the depths.

If you’ve ever heard of a global-warming solution involving fertilizing the ocean with iron, this is what people have been talking about. Dump iron in the surface waters and phytoplankton multiply like crazy, pulling extra carbon dioxide out of the air, dying, and sinking. Oceanographers were once hopeful about this, but actual experiments – involving 100 square kilometers near the Galapagos and in the Southern Ocean – made them suspect that very little carbon made it down to the depths. The VERTIGO results indicate their skepticism was warranted, but might also suggest that some parts of the ocean are better places to try than others.

A computing team at Berkeley and Texas A&M has finally enabled us to go birding in someone else’s backyard. Their project – the vaguely naughty-sounding Cone Sutro Forest Collaborative Observatory for Natural Environments project – takes you out onto Craigslist founder Craig Newmark’s back deck and puts a pan-tilt-zoom camera at your fingertips. There’s an array of well-stocked feeders plus a bird-bath and some alluringly red hummingbird flowers. Sign in, and you can move the camera, take snapshots of rare beauties (like this house sparrow pair) and identify or argue over the resulting pictures.

The only hitch is that there’s only one camera, and it’s simultaneously at the fingertips of everyone else. Satisfying the wishes of so many users probably makes a really interesting problem for coders, but at our end it’s a lot like being a pair of binoculars that a bunch of five-year-olds are fighting over. Seasickness is a possibility. The camera constantly wheels from bird-bath to feeder and back, zooms in impossibly close on foliage, or leers at the back windows of Craig’s neighbors (the programmers wisely disabled the zoom feature for those areas).

For all the jitteriness, users have already compiled some great photos of 13 species, including black-headed grosbeak, pygmy nuthatch and Anna’s hummingbird. Somebody named “Sialia” (bluebird) has already earned more than 900 points since yesterday. (I got one point for my house sparrow, which suggests Sialia has put considerable time in already.)

The system developers hope to invent a system that remotely monitors wildlife by collecting the observations of a crowd. (They’ve got a prototype stationed in an Arkansas swamp looking for the ivory-billed woodpecker.) I like the idea of crowd wisdom, but finding rare things has always been about looking where no one else is looking. Still, give the site a spin and enjoy some San Francisco backyard birds. Then lobby for putting the next version out at Point Reyes – where hotshots like Peter Pyle and Keith Hansen have backyard bird lists around 300 species.

And we’re not talking about out-of-touch middle Americans, either. We’re talking 212 MIT grad students. When asked to anticipate CO2 levels under two emissions scenarios, more than 3/4 gave answers that would require carbon dioxide to disappear from the universe.

The authors, John Sterman and Linda Booth Sweeney, are from MIT, too – so they likely weren’t intending to take a cheap shot at MIT’s reputation. Rather, they were pointing out how tricky it is to imagine complex systems at work – and how our brains gravitate toward easy (but error prone) ways of thinking.

At the heart of the problem is our obsession with CO2 emissions and removal rates. As the MIT students demonstrate, it’s all too easy to think that if we can level off our emissions (itself an almost unimaginably remote goal at the moment), CO2 levels and temperatures will start to drop. Problem is, that misses the (dare I say it?) inconvenient truth that emissions already outpace removal by more than 2 billion tons per year. So just leveling off emissions still means a steady, uncompromising rise in atmospheric CO2.

The authors do a nice job of drawing comparisons: We typically deal with the world on some sort of a “wait-and-see” basis. Is the kettle boiling? Wait for the whistle. Is the bathtub full? Turn off the tap. That’s how most of us operate. When even slightly more complicated relationships are left to the public to decide, it’s always a struggle: look at the battles we’re still fighting to get people to wear seat belts and vaccinate their kids.

If reasonably smart people are prone to making foolish errors when it comes to climate change, it’s even easier to lead them into those errors with some sophistry. That’s what Myron Ebell, of the Competitive Enterprise Institute, has made a career doing: popping off fallacies and ad hominem attacks with the unerring regularity of Wallace’s automatic porridge-flinger.

He probably doesn’t realize it, but he got his comeuppance this month, in a Vanity Fair interview. He scoffed his way through his questions, insulting climatologists’ pedigrees rather than addressing their research (NASA’s Jim Hansen “isn’t even a climate scientist!” Right, he’s, uh, an atmospheric physicist. Your point?). Fortunately, interviewer Michael Shnayerson cut away regularly to get counterpoints from actual climate scientists.

Ebell’s ability to lap up disapproval, badmouth the opposition and crow about his own brilliance is infuriating, especially for someone whose own climate credentials add up to an undergrad degree in philosophy. But it reminds me why critical thinking is still the most important subject in school.

Documentary director Martin Durkin takes unsavoriness one step farther. In “The Great Global Warming Swindle,” Durkin falsified data on temperature graphs and claimed they came from NASA when in fact they came from an obscure journal populated by other climate skeptics. And all this in the name of revealing some sort of carefully concealed truth to the public.

Tellingly, e-mails from the U.K.’s Times asking Durkin for explanation received unprintable replies. When you don’t have anyplace left to argue from, you start yelling. Squeaky wheels are the same the world over.

I’d write something unprintable myself, but I’m holding fast to the belief that people can still tell a shaky argument by the way it’s delivered. Shrill, blustery, self-congratulating, or circular? Not interested. Reasonable premise, reliable evidence, intact logic? Let’s talk.

And now for something completely different: Small bees with big tongues.

Ecological fieldwork consists of fascinating questions answered with excruciating amounts of work. Take this study, by Brendan Borrell of the University of California, Berkeley. His aim: to understand nectar drinking in orchid bees ranging in size from teensy (50 mg) to just pretty small (900 mg).

Orchid bees, we learn, drink nectar by sucking it up through a straw-shaped proboscis. That makes them a breed apart from bumblebees, which lap the stuff up like dogs. The straw method works nicely over short lengths but, as anyone who has ever tried to get a jumbo Wendy’s Frostie started knows, it runs into trouble when the straw is long and the fluid is viscous (as with super-sweet varieties of nectar). The American Naturalist article puts it like this (I love it):

In suction feeding, resistance to fluid flow increases with proboscis length, but in capillary-based lapping, the amount of nectar that can be extracted per lap is proportional to the surface area of the tongue (Harder 1983a, 1986; Kingsolver and Daniel 1983, 1995). As predicted by the suction-feeding model, the relationship between energy intake rate and proboscis length was less than the direct proportionality predicted by a simple analysis of the Hagen-Poiseuille equation.

Anyway, learning the details required catching 750 bees of 32 species, getting them to stick out their tongues to be measured, weighing them before and after they fed from a “standard” nectar intake rate measurer, then dissecting them to measure individual body parts.

At the heart of the matter seems to be the abundance of small orchid bees (<100 mg) with very long tongues (up to 25 mm!). How does such a wisp of a bee work up the suction? And wouldn’t it be better off visiting shorter flowers with a shorter tongue? And, come to think of it, isn’t nectar supposed to be a reward for visiting? Shouldn’t the plant make it easier to visit, not harder?

Well, Borrell, suggests, from the bee’s point of view the answer is competition: long-tongued bees have the hassle of unspooling, slurping through and re-coiling that garden hose at each visit, but the deep flowers they visit are less likely to have been sucked dry.

The plant has its own interesting perspective. For widely dispersed plants, what good is attracting pipsqueak bees? They won’t have the stamina to make it over to the next individual. They want to attract large, athletic bees from the other end of the meadow. They do that by offering especially sweet nectar and hiding it away in deep flowers. Around those kinds of plants, if you’re a small bee with a long tongue, you’ve got it made.

But waiting at the end of all this, like a punch line, is the revelation that the flowers feeding these bees may not even be orchids. Many orchids don’t produce nectar, and orchid bees, bless their hearts, are their eternal dupes. The flowers lure the male bees (only the males) with strange scents including vanilla. As the glossy insects plunge in head-first, they get tagged with a sticky basket of pollen and sent on their way. The bees do collect some of the perfume, but no one’s completely sure what they use it for.

An examination of their [orchids’] many beautiful contrivances will exalt the whole vegetable kingdom in most persons’ estimation. I fear, however, that the necessary details are too minute and complex for any one who has not a strong taste for Natural History.

***Spoiler alert: If you are my landlord, you might be a bit alarmed at some of the following***

A couple of months ago the landlords of Scribble Central Command fell behind on the lawnmowing schedule, and the tenants of SCC didn’t pick up the slack. It was the middle of the rainy season, and the next time we turned around the lawn had leapt up into an untameable green mess that looked like it ate lawnmower blades for breakfast.

At first I felt a bit guilty, being one of the few renters on the block, with the unruly lawn to prove it. But as the weeds grew in burliness and confidence, I started to share their pride. Yellow, white, and pink flowers craned over the timid greenness of other yards.

I started wading through the clover during coffee breaks, watching ladybugs pounce on aphids and strange, skinny, scarlet-and-black beetles post up at the tips of grass stems, motionless. The profusion, and the speed with which it had arrived, was amazing. Just how much carbon had been fixed, anyway, right here in the sideyard, since I went to Germany?

Enter the Scribble Climate Experiment.

Goal: describe the ScribbleYard’s ecological impact precisely enough to permit number-dropping at science-y parties but rudimentarily enough to allow time for surfing in the afternoon. Since these results will hardly stand up to scientific scrutiny, it also seemed a good idea to limit my use of resources.

So, using my letter-opening scissors, I clipped a patch of the lawn down to bare earth (sorry landlords). The patch was roughly 0.312 square meters, or the size of one of the tires the completely anonymous housemate had, fortuitously, just changed on his road bike. I counted the number of stems of each species in my sample except for the grass (too hard to identify, not enough of it), chucked it into two cardboard boxes and put it in the back of my car to bake in the sun for a few days.

What do you know – we’ve got some heavy duty weeds in our yard. Massive growths of Medicago polymorpha (California burclover) suggest that our lawn is low in nitrogen and high in phosphorus. They also have really cool, spiny peapods that swirl into a compact, nearly spherical helix.

There’s also a lot of Geranium dissectum. There’s less Convolvulus arvensis (field bindweed) and Malva parviflora (little mallow), but they are more formidable. The bindweed, a vine related to morning glory, is so tenacious that its seeds can germinate after 60 years and suggestions for suppressing it veer toward the desperate: e.g., cover the earth with overlapping sheets of black polyethylene. The mallow can get to five feet tall and, apparently, quickly grows a woody taproot that is very difficult to remove. And these are weed experts using the word “difficult.”

In amongst it all is Erodium moschatum (whitestem filaree), which is the plant sticking its cool needly fruits into the sky at the top of this seemingly endless post.

But the really staggering part is one of those party-droppable numbers. Figuring that about 56% of the 245 sq. meter sideyard was covered with a profusion similar to what was in my sample tire plot, that means upwards of 49 thousand burclover stems and 70 thousand geranium stems. Add in the other species and there’s roughly 126,633 stems out there in the mini-forest. In two months. Cool, huh? More results to come…

About the Scribbler

Hugh Powell is a little weary of big-ticket items like Pluto, the Mars rover, and small fossilized humans getting all the science news coverage. Keep an eye out here for wisps and scraps you won't find anywhere else. Particularly about the ocean, which is really cool and, honestly speaking, much bigger than you think.